Instead of trying to come up with my own description of what this thing is it's better to simply let this thing explain itself. Just know that it is awesome and that you should check it out.
"This is an algorithmically-generated map of the musical genre-space.
Genres and artists are positioned by code and data, adjusting for
legibility, but the underlying vectors are less interesting that the
juxtaposition and clusters that they produce, so the axes have been
deliberately left unlabeled and uncalibrated. You are invited to
imagine your own qualities and magnitudes that the geometry might
be expressing. I may occasionally spin the axes just to see what happens.
Click anything to hear an example of what it sounds like.
Click the >> on a genre to see a map of it's artists"